Industrial Maintenance Solutions

Machinery that operates at speeds below 600 rpm falls under the category of low-speed machines. These machines are typically large and possess high rotating inertias, making them crucial components of the production line. Although these machines are less prone to breakdowns, they are considered critical, and their failure can result in enormous production losses, significant downtime, and substantial replacement costs. Historically, there has been limited interest in the condition monitoring of these machines due to their infrequent failures. The parts of these machines that necessitate condition monitoring are primarily the bearings and gears in motion. This article will cover modern and innovative techniques for monitoring the condition of low-speed machinery, with a particular emphasis on monitoring the condition of rolling element bearings. Monitoring low-speed bearings present unique challenges. In the case of high-speed bearings, vibration analysis, thermography, and wear deb...

BY HASANUR JAMAL MOLLA, SAAD H. AL-DOSSARY, TARIQ NADEEM, AND MOHAMMAD F. AL-SHIHRI. V arnish is an organic residue produced by irreversible chemical degradation of mineral oil lubricants. It can lead to filter plugging, restricted oil flow, poor heat transfer, valve sticking, fail-to-start conditions, and unit trips. Varnish on Spool Valves Varnish on gear Varnish on Journal  Bearing During rotating equipment operation, heat generated due to friction degrades the oil and produces very small byproduct particles that settle throughout the system as varnish. Spark discharges from static charge buildup in the lubricating oil filters play a key role in its formation. Over time, these particles attach themselves to surfaces throughout the turbine, producing a sticky film. As varnish builds up, performance of rotating equipment su ff ers. A variety of varnish removal systems are available in the market. As the conversion between soluble and insoluble varnish is a physical equilibr...

KEY TAKEAWAYS Dry film lubricants are able to face the challenge of providing the corrosion resistant lubrication required for machines operating in extreme conditions such as under heavy loads and at very high or low temperatures. From a lubrication point of view, extreme operational conditions may not commonly occur in every industry, but in some sectors such as defense and aerospace they are encountered quite often. These challenging conditions may include: Very high or very low temperatures Variable temperatures High or low surface speeds on shafts The presence of a vacuum Inaccessibility for maintenance or re-lubrication The presence of vibrations, extreme loads and stresses Contaminants generated by processes Petroleum-based lubricating substances work effectively only when: Operating temperatures are in the broad range of -4°F to 212°F (-20°C to 100°C) Tribology parameters enable the lubricant film to be formed within int...

J ournal or plain bearings consist of a shaft or journal which rotates freely in a supporting metal sleeve or shell. There are no rolling elements in these bearings. Their design and construction may be relatively simple, but the theory and operation of these bearings can be complex. This article concentrates on oil- and grease-lubricated full fluid film journal bearings; but first a brief discussion of pins and bushings, dry and semilubricated journal bearings, and tilting-pad bearings. Low-speed pins and bushings are a form of journal bearing in which the shaft or shell generally does not make a full rotation. The partial rotation at low speed, before typically reversing direction, does not allow for the formation of a full fluid film and thus metal-to-metal contact does occur within the bearing. Pins and bushings continually operate in the boundary lubrication regime. These types of bearings are typically lubricated with an extreme pressure (EP) grease to aid in suppo...